<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<link rel="stylesheet" href="./css/index.css" />
<title>记事本</title>
</head>
<body>

<!-- 主体区域 -->
<section id="app">
  <!-- 输入框 -->
  <header class="header">
    <h1>小黑记事本</h1>
    <input @keyup.enter="add()" v-model="todoName" placeholder="请输入任务" class="new-todo" />
    <button @click="add()" class="add">添加任务</button>
  </header>
  <!-- 列表区域 -->
  <section class="main">
    <ul class="todo-list">
      <li class="todo" v-for="(item,index) in list" :key="item.id">
        <div class="view">
          <span class="index">{{index + 1}}.</span> <label>{{item.name}}</label>
          <button  @click="del(item.id)" class="destroy"></button>
        </div>
      </li>
    </ul>
  </section>
  <!-- 统计和清空 -->
  <footer class="footer" v-show="list.length>0">
    <!-- 统计 -->
    <span class="todo-count">合 计:<strong> {{list.length}} </strong></span>
    <!-- 清空 -->
    <button @click="clear" class="clear-completed">
      清空任务
    </button>
  </footer>
</section>

<!-- 底部 -->
<script src="https://cdn.jsdelivr.net/npm/vue@2.7.16/dist/vue.js"></script>
<script>

  const app = new Vue({
    el: '#app',
    data: {
        todoName:"",
        list:[
            {id: 1,name:"睡觉半小时"},
            {id: 2,name:"跑步一公里"},
            {id: 3,name:"学习一小时"},
        ]
      
    },
    methods:{
        del(id){
            this.list = this.list.filter(item =>item.id !==id )
        },
        add(){
            if(this.todoName.trim()===""){
                alert("请输入任务名称")
                return
            }
            this.list.unshift({
                id:+ new Date(),
                name:this.todoName
            })
            this.todoName=""
        },
        clear(){
            this.list=[]
        }
    }

  })

</script>
</body>
</html>